


Fire Emergency

by Noire73



Series: Grillster Prompts [1]
Category: Undertale (Video Game)
Genre: Brother W. D. Gaster, Don't do what Gaster did please, Implied Sexual Content, M/M, Partial Nudity, Sexting, prompt
Language: English
Status: Completed
Published: 2017-11-01
Updated: 2017-11-01
Packaged: 2019-01-27 22:40:26
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,847
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12592104
Author URL: https://archiveofourown.org/users/Noire73/pseuds/Noire73
Summary: [EDIT: So this had other 2 chapters but I separated them into their own stand along things. Sorry for the inconvenience.]Gaster is hard at work, but fortunately for him, the boyfriends knows how to bring him back home.





	Fire Emergency

**Author's Note:**

> A few chapters based on prompts and ideas revolving around an AU where Gaster and Grillby did became a couple. Shout out to Pyrotechniics on tumblr for giving me this ideas.

_ Damn the moment that thing fell into Waterfall,  _ that’s what Grillby thought as he cleaned the last few dishes, throwing the forks and spoons into their respective place instead of neatly placing them like he normally did. He practically ripped off his gloves, slamming them on the sink. From his distress, he almost missed a few logs he had bumped into earlier and didn’t bother to pick up. 

This was getting ridiculous.

Almost three weeks. Three weeks! That’s how long since he last saw Gaster, besides that one time he grabbed take out, half kissed him on the cheek, made a promise of spending the weekend together and jumped back to the lab. That was last week. Strumming his fingers on the counter as he calmed down, thinking about how selfish he was being. Being the Royal Scientist was a busy and hard position to have, massively more compared with just being a simple bartender job; he shouldn’t be like that. Gaster was doing good things for everyone, he had to see the bigger picture- his train of thought was interrupted when the corner of the bar hit him on his side as he walked back to the front door.

_ You know what? Fuck that _ , he thought, removing his tie.

Closing the front door, he headed for the Fire Exit, the entrance to the apartment on the top of the restaurant. Stopping a few moments on the foot of the stairs, he took a deep breath, tired from today’s shift. One of the dogs had a birthday party -unplanned, and he had to do a lot last minute preparations. Hectic was not a word he would use but it was a very close definition. Finally climbing up the steps, he moved to his bedroom, passing to the neatly organized living room and glancing inside the kitchen, feeling proud there were no dirty dishes but also too depressed to actually prepare himself something to eat. He huffed, annoyed he was about to spent another lonely night. 

Taking his shirt off, not really caring where it ended up, he took his cellphone from his pocket, checking for any updates on the social media he was subscribed to. The dogs posted the picks they took today, though some of them were mostly blurry and moved, spotting himself in the background of some of them. Fuku posted a couple of pictures of her and her friend, Skates, posing somewhere outside from school. At an hour she should  _ be _ in school. She would hear from him soon. Pictures of Papyrus hanging with Undyne, blurry over exaggerated photos but they were… photos… though most of them had a comment from his brother, which were puns he actually found funny. Grillby’s sense of humor was totally ruined from spending so much time with sans and Gaster… he sighed, closing the app and looking to his messanges.

Besides a few quick messages from his sister, Gerson and Muffet… there were not a single one from Gaster. No calls, no voicemail, no email… nothing. Nothing at all. Slamming his cellphone on the bed, he stood up to remove his pants when he caught himself in the mirror. It has been a while since he did, getting a bit shaken by the image he saw. He was not as buff as he used to be but constant exercise to keep his form had indeed worked if the reflexion in front of him told him the truth. Taking a closer look, the thin white lines on his arms were still visible, scars from long, grueling battles back in the day. But the ones that stuck more were the ones on his abdomen and chest. On bad days, whenever they stayed in, Gaster would look at his scars with a solemn expression that didn’t look bad on him but it really didn’t fit someone with much over enthusiastic as him. Getting caught in the act, Gaster’s smile would return to his eyes, reassuring him the scars didn’t look bad on him. The fire monster never truly believed him when he told such lies. He’s scars weren’t cool. They were mistakes. Mistakes he wished he could forget about. 

A familiar 4 notes ringtone followed by the light on his phone flashing, shook him out of his thoughts as he undid his pants. A message from Gaster. He hurriedly reached for it, unlocking it to see what it was. Disappointment was the first thing that he felt when he started reading the first message in a week he received from him. “ _ I’m sorry Grillby. I know I promised we would spend the weekend together but I’m unable to leave the office…” _ he read out loud, skimming through the rest of the message; excuses, excuses, promises, more excuses… he sighed, gripping his cell phone. Thumping his leg in annoyance, he saw himself in the mirror, burning brighter and hotter from anger. It would be a lie if Grillby said he was waiting for this weekend, but he knew his lover too well. There was nothing more tempting for Gaster than the unknown that… thing that fell to Waterfall... posed for him and his team. He was sure that nothing could really pull him away from his office even if he were to- he caught himself in the mirror again, wide eyed and with an idea on his mind. Grinning widely, he stood closer to the mirror and opened the camera app on his phone. He knew it was selfish, he knew it might not work, he also knew Gaster could get angry, but… he also knew he didn’t really care.  _ “Fuck it.” _

* * *

 

 **“Damn the moment that thing fell into Waterfall...** Gaster said slamming his fists on the desk. Being the Royal Scientist was never an easy job. It was -to some part- gratifying, knowing how much improvements had been made in the Underground; on the other side, the workload. Though it shouldn’t be that heavy like it was at this point, but the new technology that had been falling to the Garbage Dump lately had put everyone into a creative frenzy; not many got back home for days getting ideas sketched and prototyping whatever they could. 

Unfortunately for Dr. W.D. Gaster, it meant that he had to read, review and correct many of the projects his fellow scientist and engineers had submitted to him which also meant he had not been home since the frenzy started. The space under his desk had been his bed for the few couple of hours he got of sleep before someone else busted into his office. It wasn’t that bad since he technically didn’t needed any sort of… sweet, sweet heavenly rest. Especially not on his bed… covered with his soft blankets and cuddling the fluffy pillows. Or in his boyfriend’s bed… if he felt particularly lonely. 

He sighed, letting his head fall into the desk with a heavy knock echoing on his empty office, he whined pitifully into the report he was reading, gripping his phone close to his chest, lamenting he was missing another peaceful weekend with Grillby.  **“I wanna go home!”** he yelled, slammin his head on the desk a couple of times.

It was true that he was really excited the first few days he had managed to work on the piece of tech until everyone started to get an insanely amount of projects HE had to supervise before things went out of control. Of course he liked progress, of course he loved tinkering with his own projects but he really. Wanted. To go. Home. He had made a promise to his boyfriend and he detested breaking them.

Even his own private ones were left unattended, having to focus on everyone else’s, and to ensure the security and well being of everyone as a few of the prototypes had caused a bit of havoc now and then, specially from the Robotics Department, having made a self-cleaning sofa that somehow managed to get it’s... hand… cushions?, on a few prototypes from the Secret Weapon Development Dep., whom he needed to revise their electric projectiles privileges if what happened with that sofa were any indications. If King Asgore had been around those days… it would’ve been bad for Gaster. Hopefully, the King knows to steer clear from the Labs until the craze ended every time there were new discoveries.

Lifting his head a bit from the desk, he looked at the clock, 2:15 am. Grillby should be in bed by now, cozily cuddled in a bed that should be having another ungrateful, foolish and roguishly handsome monster that was currently half unconscious in his desk, laying softly along his loved one. But no-oh! The humans had to go and throw their garbage out. Didn’t they know what recycle means?

He yawned. Now it was about time for a coffee, if his sluggish movements and intense need of warmth in his old bones were a sign. As he was about to stand up, his phone vibrated, he looked at the screen to see the message he was dreading. A message from Grillby. He was sure it would be short understanding text of him forgiving Gaster for his excuses or telling him to take more care of himself or something like that. What he did end up receiving was a photo and it was… not unwelcomed. 

A medium shot photo of Grillby covered his entire screen, he was holding his phone with one hand, having taken the picture in front of a mirror, his other hand hanging on his side. There was a sly smirk on his face, arched eyebrow, and proud of himself. The doctor’s eyes travel down Grillby’s neck, his shoulder, his exposed chest, stopping at the text covering him below the abs, hiding the goods.

 

Flambabe:

* Hey handsome <3 miss me?

 

Pounding his fist on the arm rest in his chair, he couldn’t help but grip his phone just a bit tighter, a ragged breath escaping him. “ **Holy shit…”** Gaster gasped. The fire monster had never done anything like this before. Sexting, was the word? A ping on his phone made him close the picture.

 

Flambabe

* You’re missing out. I had a w _ hole _ … itinerary planned for the evening.

* And the morning.

* And the day after.

 

He read it a couple of times, catching up on the pun his lover had added to the text, feeling a bit warmer than earlier. Looking at the mess of papers (to the average eyes, to him it was a properly organized way to order all the chaos), he deadpanned. “ **Welp, this is torture.** ” Gaster said. Another ping caught him off guard. 

A photo again. This time, it dragged a whine from the scientist throat as he leaned forward until his forehead was at the edge of his desk. The second photo was a selfie of Grillby laying down on his stomach in the bed, his face covered most of the shot but ALLOWED Gaster to see his shoulder and… just a bit of butt. His feet were up and playfully crossed. 

**“Oh, stars…”** His boyfriend was tempting him but he needed to be strong. If he went out now, more things would accumulate and his workload would have no end and then he wouldn’t be able to see Grillby or his brothers and- fuck… another ping. This time, Gaster stood up a bit too quickly, answering with a just as fast:

 

Me:

* Dont. Move. BRT.

 

He pocketed his phone and with determined steps, he went to the nearest Fire alarm and pulled it. The alarm ranged through the entire Lab, ear piercing siren reaching all the way to the catwalks on the CORE. Oh, there was a fire alright, and it was waiting for him on his bed and like HELL was he holding any longer after three weeks of non-stop working. 

Making sure everyone was out of the building, he declared on the entrance.  **“There has been some issues in the Lab and we’ll be closing shop until Monday. You can go back and grab your stuff, go back to your families, enjoy the weekend, etc., etc.”** he was about to bail when he heard his people complain and argue about pending work. He added.  **“I have my hands tied, direct orders from the King.”** That always do the trick. 

Jumping to his office, he grabbed his stuff, not really wanting to leave his boyfriend’s apartment until Monday came. He tooked a quick glance at his office, sure that he was going to regret the stunt he pulled… his phone vibrated again. Licking his “lips”, he saw the last picture he received from Grillby, this time laying on his back. That tease… leaving it all to the imagination, he thought. He scrolled to look at the new message. Just a smiley. 

Throwing his lab coat into his chair, he grabbed his briefcase and hurried towards the door. When he opened it, he was in Grillby’s bedroom closing the door behind him But, where was Grillby? He took a closer look to the room, maybe he didn’t take the pictures in here at all or- a knock on the door got him out of his thoughts. Opening the door, he came face to face with who he was looking for.

**“Hey there, nice of you to pass by, it’s been awhile.”** Gaster said, leaning on the doorway with a stupid smirk.

The fire monster deadpanned.  _ “You closed the door on me.”  _ Grillby said, shifting his weight to one leg, trusting his hip to the side. Immediately, the doctor noticed the state of semi-undress his partner was, only sporting a pair of briefs. He tried not to stare much, feeling his cheekbones getting warm.

**“Oh! Um… oops?”** Gaster moved from the door to let Grillby in.  **“I… um… sorry, I jumped in a hurry.”**

_“I see that.”_ The fire chuckled. **“** _I was thinking you wouldn’t show up.”_ he said, walking slowly into the room, carrying his mug of coffee in, drowning the room with a pleasant aroma. Gaster followed behind him like hypnotized. When he stopped to place the cup on the night stand, Gaster stood almost an inch apart, ghosting his hands in the smaller man’s hips. Noticing a few blue streaks of fire, moving up from his Core, just in the middle of his chest, Gaster placed a kiss on Grillby’s shoulder, finally letting his hands make full contact. _“Eager, aren’t you?”_

**“You have no idea, what I had to do to get out off the office.”** he circled his waist, hugging him closer, nuzzling close to his lover’s neck.  **“I did missed you. A lot.”**

_ “Really, now?” _ Grillby teased, holding into the other’s arms, he undid his embrace, turning to face him, placing Gaster’s hands back on his waist. He grabbed the taller one’s tie, pulling him closer.  _ “How about you show me?” _

* * *

 

_ “You were lucky. A few more minutes and it would’ve been too late”.  _ Grillby said, sitting on the dining chair while Gaster sat in the other one by his side. At some point, they had to rest, both hungry and tired from their respectives work loads. None had really bother too much thought into dressing, Grillby had Gaster’s shirt and Gaster had only his slacks on.

**“I would’ve been here the moment you sent the first one but I had to deal with something before leaving.”**

_ “So what did you do?”  _ **“Huh?”** _ “To get out off the office. You said it like you had to kick everyone out of the Lab.” _

**“Well, something like that. I gave them the weekend off. I’ve been planning on doing that the whole week.”** Gaster said, it wasn’t a lie, he did tried, so he just hid what truly happened.

_ “Really? That was nice of you.”  _ He said, returning to his phone, scrolling through one of his social medias.  _ “So… where was the fire?”  _ Grillby deadpanned.  __

**“I have no idea what you-”** before he could continue, he had Grillby’s phone shoved in his face, it seems he wanted to show him a post of one of his “followers”.

 

TheScienceCat:

FINALLY A FREE WEEK! THANK THE ANGEL FOR WHATEVER CAUGHT ON FIRE! :D

 

Gaster looked away, faking a laughter.  **“Pfff,** **_TheScienceCat!_ ** **What an original username, wonder how long did he take for that one-”** he started saying before getting glared at. Grillby’s fingers drummed on the table, waiting for an answer.  **“-umm… heh, well... there was a small fire, yes-”**

_ “I’m not talking about the one in your pants, Gaster.” _

**“Hah! Good one, love-”**

_ “Gaster. What did you do?” _

**“...”**

_ “If you don’t tell me, you’re sleeping in the couch the whole weekend.” _

**“Aw, come on-”** Gaster’s whines were cut by the dangerous way Grillby’s flame lashed on top of his fiery head. There was always something so beautiful about witnessing the variety of emotions he could read from his boyfriend by just the way his fire moved in his body. He sighed. Nothing wasn’t worth seeing Grillby stress like that.

**“Okay, fine… I- I pulled the fire alarm.”**

“ _...” _

**“...”**

“ _ You’re sleeping on the floor.” _

**“What?!”**


End file.
